Timbaland and Metro Boomin are sitting in 11th Street Records in Las Vegas one afternoon in July, talking about the difference between a hit and a classic. “You did ‘Bad and Boujee,’ ” Timbaland notes, referring to the 2016 Migos track Metro produced. “That’s a classic.”

Metro offers his own distinction. “There might be a classic that peaks at Number 23, and another song goes Number One,” he notes, “but you can play them both 10 years later, and you might not even want to hear the One.” (For the record, “Bad and Boujee” was a classic and a Number One.)

The producers are more than qualified to speak on this subject — both have more than their share of both hits and classics. Timbaland, 52, became one of the defining beatmakers for the 1990s and 2000s by pushing acts like Missy Elliott, Aaliyah, Ginuwine, and Justin Timberlake into spaces that were at once undeniable pop and verging on the avant-garde. His work with Jay-Z includes many of the legendary rapper’s best-remembered songs, and while he’s mastered wildly disparate sound palettes, Timbaland’s intricate percussion work and industrial melodies make his beats instantly recognizable. Metro, 31, has followed in this auteurist lineage, his heavy bass and relentless bounce buoying work by rappers including Young Thug, Future, Migos, 21 Savage, and many others.